Grimsby Old Blockhouse

Grimsby Old Blockhouse is a fortified stone structure on Blockhouse Point that overlooks Old Grimsby Harbour and the beaches below. The thick walls were built to defend against sea-based invasions and protect the harbor area from attack.

This fortification was built in the 16th century under Henry VIII to protect the coast against French invasion threats. During the English Civil War, it was occupied by both sides and played a defensive role in regional conflicts.

The blockhouse demonstrates how Tudor engineers protected maritime regions and served as part of broader coastal defense strategies. Its sturdy walls still stand today as evidence of the practical military engineering approaches of that era.

Access is via a walking path that takes about twenty minutes from Old Grimsby and runs along the coastline with good views. Wear shoes with good grip, especially if conditions are wet or windy.

This blockhouse is one of three military structures on Tresco that form a defensive triangle, showing how thoroughly the island was protected against attack. Together with Cromwell's Castle and King Charles' Castle, it creates an important network of regional defense history.

Location: Tresco

Part of: Mid-16th century blockhouse and ramparts with adjacent walling and occupation deposits at Block House Point

Website: https://english-heritage.org.uk/visit/places/old-blockhouse

GPS coordinates: 49.95852,-6.32752

Latest update: December 14, 2025 13:00